Reliance Industries Ltd (RIL) is in the process of selling a 20% stake in the company’s flagship chemicals and refining business to Saudi Aramco in a deal valued at $15 billion, as the Indian company seeks to cut its massive debt and secure an assured supply of crude oil to its refineries. Chairman Mukesh Ambani, Asia’s richest man, announced the proposed transaction at the company’s 42nd annual general meeting on Monday, although the terms of the deal have not been finalized. The deal, which values the oil-to-chemicals (O2C) business at $75 billion, is part of a plan to make RIL a zero-debt company in the next 18 months.